URO-OXALIC NEPHRITIC LITHIASIS - SOME PAR TICULARITIES

In a paper published in 1974, it was reported that uro-oxalic stones a re found more often in subjects with group O than with group A blood t ypes although the proportions of these two blood types are approximate ly equivalent in the French population. The present work confirms thes e data, the ratio of group O to group A renal lithiasis being approxim ately 3 to 1. In a paper published in 1987, uro-oxalic stones were fou nd to occur preferentially on the left side : 84 on the left and 39 on the right. The present work confirms this notion since in 57 cases, s tones were bilateral in 2 cases, on the left in 39 and on the right in 16. Extra corporeal shock wave lithotripsy was performed in 40 of the 57 cases and showed that uro-oxalic stones are more resistant to shoc k-waves than the other types of stones. They are about as hard as calc ium oxalate monohydrate stones or harder in certain cases : A mean of 3 865 shock-waves were required in the 40 cases of the uro-oxalic lith iasis treated with the HM3 Dornier device, while the mean number of sh ock-waves required for all types of stones in general varies from 2 00 0 to 2 500. In 4 cases, 5 000 or 6 000 high power shock-waves (7 000 i n one session and 9 500 in two sessions) had to be used to obtain a sa tisfactory result. The calcium oxalate part of these stones is almost always composed of calcium oxalate monohydrate. The uric acid part is in general composed of anhydrous or bihydrated uric acid or red or yel low-red sodium urate. In the last series, white ammonium rate stones w ere spontaneously expelled whole or after lithotripsy fragmentation in patients without any important infection. The proportion of uro-oxali c stones, compared with all nephritic stones, was in 1974 approximatel y 5 % nearly identical to that of uric acid stones. In 1994, the propo rtion of uro-oxalic stones reached 9.8 % and the proportion of uric ac id stones fell to 2 %. These observations raise important genetic, pat hogenic and therapeutic questions.